JPS5942231A - Mechanical structure - Google Patents

Abstract

PURPOSE:To improve vibration attenuating property by a method wherein a plate material is wound into multiple layers and the plate material is contacted with each other in the condition of surface contact in case a frame structure is constituted by bending the plate material. CONSTITUTION:The plate material is wound into the multiple layers by the method of working, such as sheet metal working, press working or the like, to make the frame structure (table) 1. Each parts of the wound plate material are contacting with the neighboring plate material in the condition of surface contact. According to this method, when impact or periodical vibrating force is applied from an external source to a bed B, for example, the vibrating force is transmitted to the table 1 from the bed B, dry frictions, based on minute sliding, are generated at the contacting surfaces of the plate material constituting the table 1 of multiple layers, a vibration energy is converted into heat energy and the absorption as well as the attenuation of the vibration may be permitted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanical structure with improved vibration damping properties.

When it is necessary to improve the rigidity of a mechanical structure, static rigidity is often increased by increasing the thickness or size of the structural part or adding supporting members. but,
If the static stiffness is increased using the method described above, the mass of the structural material will also increase, so the natural frequency of the mechanical structure, which is basically determined based on the ratio of stiffness to mass, will increase. does not change, and especially the dynamic stiffness near the resonance point does not change much, so it is often insufficient to prevent self-excited vibrations such as chatter vibrations of machine tools. On the other hand, in order to prevent unstable vibrations of mechanical structures, various considerations have been made to the configuration of mechanical structures. For example, various attempts have been made and improvements have been made, such as using castings with high material damping, leaving some molding sand to increase material damping, and directly connecting the machine to the concrete foundation. However, all of the above methods have the disadvantage of being costly. On the other hand, from a cost perspective, it is advantageous to use sheet metal for mechanical structures, but in this case, care must be taken that although there is no problem in maintaining static rigidity, dynamic rigidity is Attenuation rate approximately 0.1~0.
Since the material damping of the sheet metal decreases by 0.01 to 0.04 compared to 2, it is necessary to take some kind of active measure to increase the damping.

Especially in machines with a wide operating range, it would be ideal to have some control over the vibration damping effect. In addition, for forging machines, iron-making machines, and other machines that generate large shocks during operation, there is a need to reduce the noise of the machine structures from the viewpoint of the working environment and pollution. In other words, it is desired to absorb and attenuate vibrations in order to stop the propagation of the generated shock and prevent it from propagating to other machines and buildings.

The present invention was made in view of the above situation, and
The purpose is to increase the structural damping and improve the shock absorption capacity of mechanical structures in an inexpensive manner.

The gist of the present invention to achieve the above object is that in a mechanical structure formed by folding plate materials into a frame shape, the plate materials are wound in a multi-layered manner so that the plates are in surface contact with each other; The present invention is further characterized in that it further includes means for pressing the plate material that is in surface contact with each other.

Hereinafter, a mechanical structure according to the present invention will be explained in detail based on embodiments shown in the drawings.

FIG. 1 shows a perspective appearance of a bed of a machine tool taken up as an example of a machine structure, and FIG. 2 shows an embodiment of a machine structure according to the present invention applied to the bed. Shown as an X cross-sectional view. In Fig. 2, i is a mechanical structure that forms the frame of bed B, and is a frame of any shape made by winding plate materials in multiple layers using a processing method such as sheet metal pressing. Each part of the material is in surface contact with the adjacent plate material. Note that the plate material is partially spot welded,
It may be fixed by a coupling means such as bolt fastening.

In the mechanical structure with the above configuration, when an impact or periodic excitation force is applied to the bed B from the outside, vibration force is transmitted from the bed B3 to the frame 1, causing contact between the plate materials constituting the multilayer frame 1. Dry friction occurs on the surface due to micro-sliding, and vibration energy is converted into thermal energy, which absorbs and attenuates vibrations. In addition, the propagation of vibrations from other machines or parts (2) connected to the bed B and the left type 1 is suppressed, and the generation of solid sound from the bed B itself is also reduced, so that noise prevention is also achieved.

FIG. 3 shows yet another embodiment. In this structure, a fluid pressure cylinder 2 is installed as a pressing means inside a frame 1, so that the contact pressure of the plate-like materials in surface contact can be controlled. Thereby, by adjusting the contact surface pressure, it is possible to obtain optimal vibration damping characteristics according to the vibrations generated in the mechanical structure.

As explained above, according to the present invention, a mechanical structure with increased structural damping and improved shock absorbing ability can be obtained, and it is also possible to exhibit optimal vibration damping characteristics.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a bed shown as an example of a mechanical structure to which the present invention is applied, and FIG. 2 is an embodiment of the present invention, and is a sectional view taken along line XX of the bed in FIG. FIG. 3 shows another embodiment of the present invention, in which the bed shown in FIG.
It is an X sectional view. B: Bed, 1: Frame type, 2: Fluid pressure cylinder.

Claims (2)

[Claims] (1) A mechanical structure formed by bending plate materials into a frame shape, characterized in that the plate materials are wound in a multi-layered manner and the chain plates are configured so as to be in surface contact with each other. (2) In a mechanical structure formed by bending plate materials into a frame shape, the plate materials are wound in a multi-layered manner, and the chain plates are configured so that they are in surface contact with each other, and a means for pressing the plate materials that are in surface contact is provided. A mechanical structure characterized by: